It is well known in the golfing industry that, in order to properly strike and drive a golf ball, the golfer's club must pass through certain angular positions. Further, it is also known that the rearward shoe of the golfer, opposite the forward or target shoe, must be raised at the end of a full golf swing such that the backside of the shoe is generally horizontal with respect to a vertical plane extending through the body of the golfer and perpendicular to the ground plane.
U.S. Pat. No. 3,362,023 to McMahon discloses a device which sounds an audible alarm when a certain angle is exceeded. The device uses a pair of mercury switches to detect an angular change of position. The unit, having the pair of mercury switches, is worn on the hat of a golfer. A second angle detection unit, with another mercury switch, is clipped onto the golfer's shoulder. The shoulder unit resets the hat buzzer unit.
U.S. Pat. No. 4,667,188 to Schwartz discloses a portable alarm activated by detecting an angular displacement of the alarm unit.
U.S. Pat. Nos. 5,221,088 to McTeigue and 5,372,365 to McTeigue disclose an angle detector mounted on the spine of a golfer. See FIG. 5. The angle detector is an inclinometer and preferably an accelerometer which generally continuously measures the angular displacement of the golfer's spine relative to the vertical plane. The detector is strapped to the back of the golfer.
The following patents are of general interest: U.S. Pat. No. 5,619,187 to Schmidt discloses a foot weight alarm which measures excessive weight on a foot. Excessive force generates an alarm signal. The unit has a flat pad sensor disposed beneath the foot of the user in the user's shoe. U.S. Pat. No. 5,323,650 to Fullen discloses a system for continuously measuring forces applied to the foot. A flat pad sensor, beneath the user's foot, is utilized to generate signals.
U.S. Pat. No. 4,958,145 to Morris discloses a back incline indicator. The indicator is strapped onto the user's back. U.S. Pat. No. 5,089,808 to Amirdash discloses a device giving a vibratory warning when undesired lifting position is assumed. This unit is mounted in the user's shirt pocket. An angle detection device is included in the alarm circuit.
U.S. Pat. No. 3,861,688 to Butler discloses a golf training device which includes a string or cord connected between a unit, worn on the golfer's wrist, and a club attachment.